U.S. patent application number 11/345563 was filed with the patent office on 2007-08-02 for sealant composition having reduced permeability to gas.
Invention is credited to Shoyne J. Landon.
Application Number | 20070179242 11/345563 |
Document ID | / |
Family ID | 38066391 |
Filed Date | 2007-08-02 |
United States Patent
Application |
20070179242 |
Kind Code |
A1 |
Landon; Shoyne J. |
August 2, 2007 |
Sealant composition having reduced permeability to gas
Abstract
This invention relates to a moisture-curable silylated
resin-containing composition containing, inter alia,
moisture-curable silylated resin, the cured composition exhibiting
low permeability to gas(es).
Inventors: |
Landon; Shoyne J.; (Ballston
Lake, NY) |
Correspondence
Address: |
DILWORTH & BARRESE, LLP
333 EARLE OVINGTON BLVD.
SUITE 702
UNIONDALE
NY
11553
US
|
Family ID: |
38066391 |
Appl. No.: |
11/345563 |
Filed: |
February 1, 2006 |
Current U.S.
Class: |
524/588 ;
525/106 |
Current CPC
Class: |
C08G 18/10 20130101;
C08G 18/10 20130101; C08G 18/10 20130101; C08G 2190/00 20130101;
C08J 2375/04 20130101; C08G 18/718 20130101; C08L 101/10 20130101;
B82Y 30/00 20130101; C08J 5/005 20130101; C08L 101/10 20130101;
C08G 18/4825 20130101; C08J 2300/108 20130101; C03C 27/10 20130101;
C08G 18/289 20130101; C08L 2666/02 20130101 |
Class at
Publication: |
524/588 ;
525/106 |
International
Class: |
C08L 83/04 20060101
C08L083/04 |
Claims
1. A moisture-curable silylated resin-containing composition
comprising: a) moisture-curable silylated resin, which upon curing,
provides a cured resin exhibiting permeability to gas; b) at least
one other polymer having a permeability to gas that is less than
the permeability of cured resin (a); and, optionally, c) at least
one additional component selected from the group consisting of
catalyst, adhesion promoter, filler, surfactant, UV stabilizer,
antioxidant, cure accelerator, thixotropic agent, moisture
scavenger, pigment, dye, solvent and biocide.
2. The composition of claim 1 wherein moisture-curable silylated
resin (a) is at least one member selected from the group consisting
of: (i) silylated resin obtained from the reaction of
isocyanate-terminated polyurethane prepolymer with active
hydrogen-containing organofunctional silane; (ii) silylated resin
obtained from the reaction of hydroxyl-terminated polyurethane
prepolymer with isocyanatosilane; and, (iii) silylated polymer
obtained from the reaction of polyol with isocyanatosilane.
3. The composition of claim 1 wherein moisture-curable silylated
resin (a) ranges from about 1 to about 99 weight percent of the
total composition.
4. The composition of claim 1 wherein moisture-curable silylated
resin (a) ranges from about 10 to about 50 weight percent of the
total composition.
5. The composition of claim 1 wherein moisture-curable silylated
resin (a) ranges from about 20 to about 30 weight percent of the
total composition.
6. The composition of claim 1 wherein polymer (b) is selected from
the group consisting of low density polyethylene, very low density
polyethylene, linear low density polyethylene, high density
polyethylene, polypropylene, polyisobutylene, polyvinyl acetate,
polyvinyl alcohol, polystyrene, polycarbonate, polyester, such as,
polyethylene terephthalate, polybutylene terephthalate,
polyethylene napthalate, glycol-modified polyethylene
terephthalate, polyvinylchloride, polyvinylidene chloride,
polyvinylidene fluoride, thermoplastic polyurethane, acrylonitrile
butadiene styrene, polymethylmethacrylate, polyvinyl fluoride,
polyamides, polymethylpentene, polyimide, polyetherimide, polether
ether ketone, polysulfone, polyether sulfone, ethylene
chlorotrifluoroethylene, polytetrafluoroethylene, cellulose
acetate, cellulose acetate butyrate, plasticized polyvinyl
chloride, ionomers, polyphenylene sulfide, styrene-maleic
anhydride, modified polyphenylene oxide, ethylene-propylene rubber,
polybutadiene, polychloroprene, polyisoprene, polyurethane,
styrene-butadiene-styrene, styrene-ethylene-butadiene-styrene,
polymethylphenyl siloxane and mixtures thereof.
7. The composition of claim 6 wherein polymer (b) is selected from
the group consisting of low density polyethylene, very low density
polyethylene, linear low density polyethylene, high density
polyethylene, and mixtures thereof.
8. The composition of claim 7 wherein polymer (b) is selected from
the group consisting of low density polyethylene, very low density
polyethylene, linear low density polyethylene, and mixture
thereof.
9. The composition of claim 1 wherein polymer (b) ranges from about
1 to about 99 weight percent of the total composition.
10. The composition of claim 1, wherein polymer (b) ranges from
about 5 to about 50 weight percent of the total composition.
11. The composition of claim 1, wherein polymer (b) ranges from
about 10 to about 20 weight percent of the total composition.
12. The composition of claim 1 wherein the catalyst is a tin
catalyst.
13. The composition of claim 1 wherein the tin catalyst is selected
from the group consisting of dibutyltin dilaurate,
dibutyltindiacetate, dibutyltindimethoxide, tinoctoate,
isobutyltintriceroate, dibutyltinoxide, solubilized dibutyl tin
oxide, dibutyltin bis-diisooctylphthalate, bis-tripropoxysilyl
dioctyltindibutyltin bis-acetylacetone, silylated dibutyltin
dioxide, carbomethoxyphenyl tin tris-uberate, isobutyltin
triceroate, dimethyltin dibutyrate, dimethyltin di-neodecanoate,
triethyltin tartarate, dibutyltin dibenzoate, tin oleate, tin
naphthenate, butyltintri-2-ethylhexylhexoate, tinbutyrate,
diorganotin bis .beta.-diketonates, and mixtures thereof.
14. The composition of claim 1 wherein the adhesion promoter is
selected from the group consisting of
n-2-aminoethyl-3-aminopropyltrimethoxysilane,
1,3,5-tris(trimethoxysilylpropyl)isocyanurate,
.gamma.-aminopropyltriethoxysilane,
.gamma.-aminopropyltrimethoxysilane, aminopropyltrimethoxysilane,
bis-.gamma.-trimethoxysilypropyl)amine,
N-Phenyl-.gamma.-aminopropyltrimethoxysilane,
triaminofunctionaltrimethoxysilane,
.gamma.-aminopropylmethyldiethoxysilane,
.gamma.-aminopropylmethyldiethoxysilane,
methacryloxypropyltrimethoxysilane,
methylaminopropyltrimethoxysilane,
.gamma.-glycidoxypropylethyldimethoxysilane,
.gamma.-glycidoxypropyltrimethoxysilane,
.gamma.-glycidoxyethyltrimethoxysilane,
.beta.-(3,4-epoxycyclohexyl)propyltrimethoxysilane,
.beta.-(3,4-epoxycyclohexyl) ethylmethyldimethoxysilane,
isocyanatopropyltriethoxysilane,
isocyanatopropylmethyldimethoxysilane,
.beta.-cyanoethyltrimethoxysilane,
.gamma.-acryloxypropyltrimethoxysilane,
.gamma.-methacryloxypropylmethyldimethoxysilane,
4-amino-3,3,-dimethylbutyltrimethoxysilane,
n-ethyl-3-trimethoxysilyl-2-methylpropanamine, and mixtures
thereof.
15. The composition of claim 1 wherein the filler is selected from
the group consisting of calcium carbonate, precipitated calcium
carbonate, colloidal calcium carbonate, calcium carbonate treated
with compounds stearate or stearic acid, fumed silica, precipitated
silica, silica gels, hydrophobized silicas, hydrophilic silica
gels, crushed quartz, ground quartz, alumina, aluminum hydroxide,
titanium hydroxide, clay, kaolin, bentonite montmorillonite,
diatomaceous earth, iron oxide, carbon black and graphite, mica,
talc, and mixtures thereof.
16. The composition of claim 15 wherein the filler is selected from
the group consisting of montmorillonite, sodium montmorillonite,
calcium montmorillonite, magnesium montmorillonite, nontronite,
beidellite, volkonskoite, laponite, hectorite, saponite, sauconite,
magadite, kenyaite, sobockite, svindordite, stevensite,
vermiculite, halloysite, aluminate oxides, hydrotalcite, illite,
rectorite, tarosovite, ledikite, kaolinite and, mixtures
thereof.
17. The composition of claim 16 wherein the filler is modified with
ammonium, primary alkylammonium, secondary alkylammonium, tertiary
alkylammonium quaternary alkylammonium, phosphonium derivatives of
aliphatic, aromatic or arylaliphatic amines, phosphines or sulfides
or sulfonium derivatives of aliphatic, aromatic or arylaliphatic
amines, phosphines or sulfides.
18. The composition of claim 16 wherein the filler is modified with
at least one tertiary amine compound R.sup.3 R.sup.4 R.sup.5N
and/or quaternary ammonium compound R.sup.6 R.sup.7
R.sup.8N.sup.+X.sup.- wherein R.sup.3, R.sup.4, R.sup.5, R.sup.6,
R.sup.7 and R.sup.8 each independently is an alkyl, alkenyl or
alkoxy silane group of up to 60 carbon atoms and X is an anion.
19. The composition of claim 1 wherein the surfactant is a nonionic
surfactant selected from the group consisting of polyethylene
glycol, polypropylene glycol, ethoxylated castor oil, oleic acid
ethoxylate, alkylphenol ethoxylates, copolymers of ethylene oxide
and propylene oxide and copolymers of silicones and polyethers,
copolymers of silicones and copolymers of ethylene oxide and
propylene oxide and mixtures thereof.
20. The composition of claim 19 wherein the non-ionic surfactant is
selected from the group consisting of copolymers of ethylene oxide
and propylene oxide, copolymers of silicones and polyethers,
copolymers of silicones and copolymers of ethylene oxide and
propylene oxide and mixtures thereof.
21. A sealant, adhesive or coating composition prepared with the
moisture-curable silylated resin-containing composition of claim
1.
22. A sealant, adhesive or coating composition prepared with the
moisture-curable silylated resin-containing composition of claim
2.
23. A sealant, adhesive or coating composition prepared with the
moisture-curable silylated resin-containing composition of claim
18.
24. The cured silylated resin-containing composition of claim
1.
25. The cured silylated resin-containing composition of claim
2.
26. The cured silylated resin-containing composition of claim 18.
Description
FIELD OF THE INVENTION
[0001] This invention relates to moisture-curable silylated
resin-containing compositions having reduced gas permeability and
methods of using these compositions. The compositions are
particularly well suited for use in the window area as an
insulating glass sealant and in applications such as coatings,
adhesives and gaskets.
BACKGROUND OF THE INVENTION
[0002] Moisture-curable compositions are well known for their use
as sealants. In the manufacture of Insulating Glass Units (IGU),
for example, panels of glass are placed parallel to each other and
sealed at their periphery such that the space between the panels,
or the inner space, is completely enclosed. The inner space is
typically filled with a gas or mixture of gases of low thermal
conductivity.
[0003] Current room temperature curable (RTC) silicone sealant,
while effective to some extent, still have only a limited ability
to prevent the loss of low thermal conductivity gas, e.g., argon,
from the inner space of an IGU. Over time, the gas will escape
reducing the thermal insulation effectiveness of the IGU to the
vanishing point.
[0004] A need therefore exists for an RTC composition of reduced
gas permeability compared to that of known RTC compositions. When
employed as the sealant for an IGU, an RTC composition of reduced
gas permeability will retain the intra-panel insulating gas of an
IGU for a longer period of time compared to that of a more
permeable RTC composition and therefore will extend the insulating
properties of the IGU over a longer period of time.
SUMMARY OF THE INVENTION
[0005] The present invention is based on the discovery that
moisture-curable silylated resin-containing composition combined
with at least one other polymer having a permeability to gas that
is less than the permeability of cured resin upon curing exhibits
reduced permeability to gas. The composition is especially suitable
for use as a sealant where high gas barrier properties together
with the desired characteristics of softness, processability and
elasticity are important performance criteria.
[0006] In accordance with the present invention, there is provided
a moisture-curable silylated resin-containing composition
comprising: [0007] a) moisture-curable silylated resin, which upon
curing, provides a cured resin exhibiting permeability to gas;
[0008] b) at least one other polymer having a permeability to gas
that is less than the permeability of cured resin (a); and,
optionally, [0009] c) at least one additional component selected
from the group consisting of catalyst, adhesion promoter, filler,
surfactant, UV stabilizer, antioxidant, cure accelerator,
thixotropic agent, moisture scavenger, pigment, dye, solvent and
biocide.
[0010] When used as a gas barrier, e.g., in the manufacture of an
IGU, the foregoing composition reduces the loss of gas(es) thus
providing a longer service life of the article in which it is
employed.
DETAILED DESCRIPTION OF THE INVENTION
[0011] In accordance with the present invention, the
moisture-curable silylated resin-containing composition of the
present invention is a resinous composition comprising: a)
moisture-curable silylated resin, which upon curing, provides a
cured resin i.e., hydrolyzed and subsequently crosslinked,
silylated polyurethane (SPUR) resin exhibiting permeability to gas,
in intimate admixture with b) at least one other polymer having a
permeability to gas that is less than the permeability of cured
resin (a); and, optionally, c) at least one additional component
selected from the group consisting of catalyst, adhesion promoter,
filler, surfactant, UV stabilizer, antioxidant, cure accelerator,
thixotropic agent, moisture scavenger, pigment, dye, solvent and
biocide.
[0012] The compositions of the invention are useful for the
manufacture of sealants, coatings, adhesives, gaskets, and the
like, and are particularly suitable for use in sealants intended
for insulating glass units.
[0013] The moisture-curable silylated resin (a) which can be
employed in the present invention are known materials and in
general can be obtained by (i) reacting an isocyanate-terminated
polyurethane (PUR) prepolymer with a suitable silane, e.g., one
possessing both hydrolyzable functionality, such as, alkoxy etc.,
and active hydrogen-containing functionality such as mercaptan,
primary and secondary amine, preferably the latter, etc., or by
(ii) reacting a hydroxyl-terminated PUR prepolymer with a suitable
isocyanate-terminated silane, e.g., one possessing one to three
alkoxy groups. The details of these reactions, and those for
preparing the isocyanate-terminated and hydroxyl-terminated PUR
prepolymers employed therein can be found in, amongst others: U.S.
Pat. Nos. 4,985,491, 5,919,888, 6,207,794, 6,303,731, 6,359,101 and
6,515,164 and published U.S. Patent Application Nos. 2004/0122253
and 2005/0020706 (isocyanate-terminated PUR prepolymers); U.S. Pat.
Nos. 3,786,081 and 4,481,367 (hydroxyl-terminated PUR prepolymers);
U.S. Pat. Nos. 3,627,722, 3,632,557, 3,971,751, 5,623,044,
5,852,137, 6,197,912 and 6,310,170 (moisture-curable SPUR obtained
from reaction of isocyanate-terminated PUR prepolymer and reactive
silane, e.g., aminoalkoxysilane); and, U.S. Pat. Nos. 4,345,053,
4,625,012, 6,833,423 and published U.S. Patent Application
2002/0198352 (moisture-curable SPUR obtained from reaction of
hydroxyl-terminated PUR prepolymer and isocyanatosilane). The
entire contents of the foregoing U.S. patent documents are
incorporated by reference herein.
[0014] The moisture-curable silylated resin (a) of the present
invention may also be obtained by (iii) reacting isocyanatosilane
directly with polyol.
(a) Moisture-Curable SPUR Resin Obtained from Isocyanate-Terminated
PUR Prepolymer
[0015] The isocyanate-terminated PUR prepolymers are obtained by
reacting one or more polyols, advantageously, diols, with one or
more polyisocyanates, advantageously, diisocyanates, in such
proportions that the resulting prepolymers will be terminated with
isocyanate. In the case of reacting a diol with a diisocyanate, a
molar excess of diisocyanate will be employed.
[0016] Included among the polyols that can be utilized for the
preparation of the isocyanate-terminated PUR prepolymer are
polyether polyols, polyester polyols such as the
hydroxyl-terminated polycaprolatones, polyetherester polyols such
as those obtained from the reaction of polyether polyol with
e-caprolactone, polyesterether polyols such as those obtained from
the reaction of hydroxyl-terminated polycaprolactones with one or
more alkylene oxides such as ethylene oxide and propylene oxide,
hydroxyl-terminated polybutadienes, and the like.
[0017] Specific suitable polyols include the polyether diols, in
particular, the poly(oxyethylene) diols, the poly(oxypropylene)
diols and the poly(oxyethylene-oxypropylene) diols, polyoxyalkylene
triols, polytetramethylene glycols, polyacetals, polyhydroxy
polyacrylates, polyhydroxy polyester amides and polyhydroxy
polythioethers, polycaprolactone diols and triols, and the like. In
one embodiment of the present invention, the polyols used in the
production of the isocyanate-terminated PUR prepolymers are
poly(oxyethylene) diols with equivalent weights between about 500
and 25,000. In another embodiment of the present invention, the
polyols used in the production of the isocyanate-terminated PUR
prepolymers are poly(oxypropylene) diols with equivalent weights
between about 1,000 to 20,000. Mixtures of polyols of various
structures, molecular weights and/or functionalities can also be
used.
[0018] The polyether polyols can have a functionality up to about 8
but advantageously have a functionality of from about 2 to 4 and
more advantageously, a functionality of 2 (i.e., diols). Especially
suitable are the polyether polyols prepared in the presence of
double-metal cyanide (DMC) catalysts, an alkaline metal hydroxide
catalyst, or an alkaline metal alkoxide catalyst; see, for example,
U.S. Pat. Nos. 3,829,505, 3,941,849, 4,242,490, 4,335,188,
4,687,851, 4,985,491, 5,096,993, 5,100,997, 5,106,874, 5,116,931,
5,136,010, 5,185,420, and 5,266,681, the entire contents of which
are incorporated here by reference. Polyether polyols produced in
the presence of such catalysts tend to have high molecular weights
and low levels of unsaturation, properties of which, it. is
believed, are responsible for the improved performance of inventive
retroreflective articles. The polyether polyols preferably have a
number average molecular weight of from about 1,000 to about
25,000, more preferably from about 2,000 to about 20,000, and even
more preferably from about 4,000 to about 18,000. The polyether
polyols preferably have an end group unsaturation level of no
greater than about 0.04 milliequivalents per gram of polyol. More
preferably, the polyether polyol has an end group unsaturation of
no greater than about 0.02 milliequivalents per gram of polyol.
Examples of commercially available diols that are suitable for
making the isocyanate-terminate PUR prepolymer include ARCOL R-1819
(number average molecular weight of 8,000), E-2204 (number average
molecular weight of 4,000), and ARCOL E-2211 (number average
molecular weight of 11,000).
[0019] Any of numerous polyisocyanates, advantageously,
diisocyanates, and mixtures thereof, can be used to provide the
isocyanate-terminated PUR prepolymers. In one embodiment, the
polyisocyanate can be diphenylmethane diisocyanate ("MDI"),
polymethylene polyphenylisocyanate ("PMDI"), paraphenylene
diisocyanate, naphthylene diisocyanate, liquid
carbodiimide-modified MDI and derivatives thereof, isophorone
diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, toluene
diisocyanate ("TDI"), particularly the 2,6-TDI isomer, as well as
various other aliphatic and aromatic polyisocyanates that are
well-established in the art, and combinations thereof.
[0020] Silylation reactants for reaction with the
isocyanate-terminated PUR prepolymers described above must contain
functionality that is reactive with isocyanate and at least one
readily hydrolyzable and subsequently crosslinkable group, e.g.,
alkoxy. Particularly useful silylation reactants are the
aminosilanes, especially those of the general formula: ##STR1##
wherein R.sup.1 is hydrogen, alkyl or cycloalkyl of up to 8 carbon
atoms or aryl of up to 8 carbon atoms, R.sup.2 is an alkylene group
of up to 12 carbon atoms, optionally containing one or more
heteroatoms, each R.sup.3 is the same or different alkyl or aryl
group of up to 8 carbon atoms, each R.sup.4 is the same or
different alkyl group of up to 6 carbon atoms and x is 0, 1 or 2.
In one embodiment, R.sup.1 is hydrogen or a methyl, ethyl, propyl,
isopropyl, n-butyl, t-butyl, cyclohexyl or phenyl group, R.sup.2
possesses 1 to 4 carbon atoms, each R.sup.4 is the same or
different methyl, ethyl, propyl or isopropyl group and x is 0.
[0021] Specific aminosilanes for use herein include
aminopropyltrimethoxysilane, aminopropyltriethoxysilane,
aminobutyltriethoxysilane,
N-(2-aminoethyl-3-aminopropyl)triethoxysilane,
aminoundecyltrimethoxysilane, and aminopropylmethyldiethoxysilane,
for example. Other suitable aminosilanes include, but are not
limited to phenylaminopropyltriemthoxy silane,
methylaminopropyltriemthoxysilane, n-butylaminopropyltrimethoxy
silane, t-butyl aminopropyltrimethoxysilane,
cyclohexylaminopropyltrimethoxysilane, dibutylmaleate
aminopropyltriemthoxysilane, dibutylmaleate-substituted
4-amino-3,3-dimethylbutyl trimethoxy silane,
N-methyl-3-amino-2-methylpropyltriemthoxysilane,
N-ethyl-3-amino-2-methylpropyltrimethoxysilane,
N-ethyl-3-amino-2-methylpropyidiethoxysilane,
N-ethyl-3-amino-2-methylpropyoltriethoxysilane,
N-ethyl-3-amino-2-methylpropylmethyidimethoxysilane,
N-butyl-3-amino-2-methylpropyltriemthoxysilane, 3
-(N-methyl-3-amino-1-methyl-1-ethoxy)propyltrimethoxysi lane,
N-ethyl-4-amino-3,3-dimethylbutyidimethoxymethylsilane and
N-ethyl-4-amino-3,3-dimethylbutyltrimethoxysilane.
[0022] A catalyst will ordinarily be used in the preparation of the
isocyanate-terminated PUR prepolymers. Advantageously, condensation
catalysts are employed since these will also catalyze the cure
(hydrolysis followed by crosslinking) of the SPUR resin component
of the curable compositions of the invention. Suitable condensation
catalysts include the dialkyltin dicarboxylates such as dibutyltin
dilaurate and dibutyltin acetate, tertiary amines, the stannous
salts of carboxylic acids, such as stannous octoate and stannous
acetate, and the like. In one embodiment of the present invention,
dibutyltin dilaurate catalyst is used in the production of the PUR
prepolymer. Other useful catalysts include zirconium complex KAT
XC6212, K-KAT XC-A209 available from King Industries, Inc.,
aluminum chelate TYZER.RTM. types available from DuPont Company,
and KR types available from Kenrich Petrochemical, Inc., and other
organic metal, such as Zn, Co, Ni, and Fe, and the like.
(b) Moisture-Curable SPUR Resins Obtained from Hydroxyl-Terminated
PUR Prepolymers
[0023] The moisture-curable SPUR resin can, as previously
indicated, be prepared by reacting a hydroxyl-terminated PUR
prepolymer with an isocyanatosilane. The hydroxyl-terminated PUR
prepolymer can be obtained in substantially the same manner
employing substantially the same materials, i.e., polyols,
polyisocyanates and optional catalysts (preferably condensation
catalysts), described above for the preparation of
isocyanate-terminated PUR prepolynmers the one major difference
being that the proportions of polyol and polyisocyanate will be
such as to result in hydroxyl-termination in the resulting
prepolymer. Thus, e.g., in the case of a diol and a diisocyanate, a
molar excess of the former will be used thereby resulting in
hydroxyl-terminated PUR prepolymer.
[0024] Useful silylation reactants for the hydroxyl-terminated SPUR
resins are those containing isocyanate termination and readily
hydrolizable functionality, e.g., 1 to 3 alkoxy groups. Suitable
silylating reactants are the isocyanatosilanes of the general
formula: ##STR2## wherein R.sup.5 is an alkylene group of up to 12
carbon atoms, optionally containing one or more heteroatoms, each
R.sup.6 is the same or different alkyl or aryl group of up to 8
carbon atoms, each R.sup.7 is the same or different alkyl group of
up to 6 carbon atoms and y is 0, 1 or 2. In one embodiment, R.sup.5
possesses 1 to 4 carbon atoms, each R.sup.7 is the same or
different methyl, ethyl, propyl or isopropyl group and y is 0.
[0025] Specific isocyanatosilanes that can be used herein to react
with the foregoing hydroxyl-terminated PUR prepolymers to provide
moisture-curable SPUR resins include
isocyanatopropyltrimethoxysilane, isocyanatoisopropyl
trimethoxysilane, isocyanato-n-butyltrimethoxysilane,
isocyanato-t-butyltrimethoxysilane,
isocyanatopropyltriethoxysilane,
isocyanatoisopropyltriethoxysilane,
isocynato-n-butyltriethoxysilane,
isocyanato-t-butyltriethoxysilane, and the like.
(c) Moisture-Curable SPUR Resins Obtained from Reacting
Isocyanatosilane Directly with a Polyol
[0026] The moisture-curable SPUR resins of the present invention
can be obtained from one or more polyols, advantageously, diols,
reacting directly with isocyanatosilane without the initial
formation of a polyurethane prepolymer. The materials, i.e.,
polyols and silanes (e.g., one possessing both hydrolysable and
isocyanato functionality), useful for this approach to producing
moisture-curable SPUR resin are described above. As such, suitable
polyols include, hydroxy-terminated polyols having a molecular
weight between about 4,000 to 20,000. However, mixtures of polyols
of various structures, molecular weights and/or functionalities can
also be used. Suitable isocyanatosilanes used to react with the
foregoing polyols to provide moisture-curable SPUR resins are
described above.
[0027] The urethane prepolymer synthesis and subsequent silylation
reaction, as well as the direct reaction of polyol and
isocyanatosilane are conducted under anhydrous conditions and
preferably under an inert atmosphere, such as a blanket of
nitrogen, to prevent premature hydrolysis of the alkoxysilane
groups. Typical temperature range for both reaction steps, is
0.degree. to 150.degree. C., and more preferably between 60.degree.
and 90.degree. C. Typically, the total reaction time for the
synthesis of the silylated polyurethane is between 4 to 8
hours.
[0028] The synthesis is monitored using a standard titration
technique (ASTM 2572-87) or infrared analysis. Silylation of the
urethane prepolymers is considered complete when no residual --NCO
can be detected by either technique.
[0029] The silicone composition of the present invention further
comprises at least one other polymer (b) exhibiting permeability to
a gas, or mixture of gases, that is less than the permeability of
moisture-curable silylated resin (a). Suitable polymers include
polyethylenes, such as, low density polyethylene (LDPE), very low
density polyethylene (VLDPE), linear low density polyethylene
(LLDPE) and high density polyethylene (HDPE); polypropylene (PP),
polyisobutylene (PIB), polyvinyl acetate(PVAc), polyvinyl alcohol
(PVoH), polystyrene, polycarbonate, polyester, such as,
polyethylene terephthalate (PET), polybutylene terephthalate (PBT),
polyethylene napthalate (PEN), glycol-modified polyethylene
terephthalate (PETG); polyvinylchloride (PVC), polyvinylidene
chloride, polyvinylidene floride, thermoplastic polyurethane (TPU),
acrylonitrile butadiene styrene (ABS), polymethylmethacrylate
(PMMA), polyvinyl fluoride (PVF), Polyamides (nylons),
polymethylpentene, polyimide (PI), polyetherimide (PEI), polether
ether ketone (PEEK), polysulfone, polyether sulfone, ethylene
chlorotrifluoroethylene, polytetrafluoroethylene (PTFE), cellulose
acetate, cellulose acetate butyrate, plasticized polyvinyl
chloride, ionomers (Surtyn), polyphenylene sulfide (PPS),
styrene-maleic anhydride, modified polyphenylene oxide (PPO), and
the like and mixture thereof.
[0030] Polymer(s) (b) can also be elastomeric in nature, examples
include, but are not limited to, ethylene-propylene rubber (EPDM),
polybutadiene, polychloroprene, polyisoprene, polyurethane (TPU),
styrene-butadiene-styrene (SBS), styrene-ethylene-butadiene-styrene
(SEEBS), polymethylphenyl siloxane (PMPS), and the like.
[0031] These polymers can be blended either alone or in
combinations or in the form of coplymers, e.g. polycarbonate-ABS
blends, polycarbonate polyester blends, grafted polymers such as,
silane-grafted polyethylenes, and silane-grafted polyurethanes.
[0032] In one embodiment of the present invention, polymer(s) (b)
is selected from the group consisting of low density polyethylene
(LDPE), very low density polyethylene (VLDPE), linear low density
polyethylene (LLDPE), high density polyethylene (HDPE), and
mixtures thereof. In another embodiment of the invention,
polymer(s) (b) is selected from the group consisting of low density
polyethylene (LDPE), very low density polyethylene (VLDPE), linear
low density polyethylene (LLDPE), and mixture thereof. In yet
another embodiment of the present invention, polymer (b) is linear
low density polyethylene (LLDPE).
[0033] Catalysts typically used in the preparation of the above
mentioned urethane prepolymers as well as the related silylated
polyurethanes (SPUR) include, those known to be useful for
facilitating crosslinking in silicone sealant compositions. The
catalyst may include metal and non-metal catalysts. Examples of the
metal portion of the metal condensation catalysts useful in the
present invention include tin, titanium, zirconium, lead, iron
cobalt, antimony, manganese, bismuth and zinc compounds.
[0034] In one embodiment of the present invention, tin compounds
useful for facilitating crosslinking in silicone sealant
compositions include: tin compounds such as dibutyltindilaurate,
dibutyltindiacetate, dibutyltindimethoxide, tinoctoate,
isobutyltintriceroate, dibutyltinoxide, solubilized dibutyl tin
oxide, dibutyltin bis-diisooctylphthalate, bis-tripropoxysilyl
dioctyltin, dibutyltin bis-acetylacetone, silylated dibutyltin
dioxide, carbomethoxyphenyl tin tris-uberate, isobutyltin
triceroate, dimethyltin dibutyrate, dimethyltin di-neodecanoate,
triethyltin tartarate, dibutyltin dibenzoate, tin oleate, tin
naphthenate, butyltintri-2-ethylhexylhexoate, and tinbutyrate, and
the like. In still another embodiment, tin compounds useful for
facilitating crosslinking in silicone sealant compositions are
chelated titanium compounds, for example, 1,3-propanedioxytitanium
bis(ethylacetoacetate); di-isopropoxytitanium
bis(ethylacetoacetate); and tetra-alkyl titanates, for example,
tetra n-butyl titanate and tetra-isopropyl titanate. In yet another
embodiment of the present invention, diorganotin bis
.beta.-diketonates is used for facilitating crosslinking in
silicone sealant composition.
[0035] In one aspect of the present invention, the catalyst is a
metal catalyst. In another aspect of the present invention, the
metal catalyst is selected from the group consisting of tin
compounds, and in yet another aspect of the invention, the metal
catalyst is dibutyltin dilaurate.
[0036] The silicone composition of the present invention can
include one or more alkoxysilanes as adhesion promoters. In one
embodiment, the adhesion promoter can be a combination
N-2-aminoethyl-3-aminopropyltrimethoxysilane and
1,3,5-tris(trimethoxysilylpropyl)isocyanurate. Other adhesion
promoters useful in the present invention include
N-2-aminoethyl-3-aminopropyltriethoxysilane,
.gamma.-aminopropyltriethoxysilane,
.gamma.-aminopropyltrimethoxysilane, aminopropyltrimethoxysilane,
bis-.gamma.-trimethoxysilypropyl)amine,
N-Phenyl-.gamma.-aminopropyltrimethoxysilane,
triaminofunctionaltrimethoxysilane,
.gamma.-aminopropylmethyldiethoxysilane,
.gamma.-aminopropylmethyldiethoxysilane,
methacryloxypropyltrimethoxysilane,
methylaminopropyltrimethoxysilane,
.gamma.-glycidoxypropylethyldimethoxysilane,
.gamma.-glycidoxypropyltrimethoxysilane,
.gamma.-glycidoxyethyltrimethoxysilane,
.beta.-(3,4-epoxycyclohexyl)propyltrimethoxysilane,
.beta.-(3,4-epoxycyclohexyl) ethylmethyldimethoxysilane,
isocyanatopropyltriethoxysilane,
isocyanatopropylmethyldimethoxysilane,
.beta.-cyanoethyltrimethoxysilane,
.gamma.-acryloxypropyltrimethoxysilane,
.gamma.-methacryloxypropylmethyldimethoxysilane,
4-amino-3,3,-dimethylbutyltrimethoxysilane,
N-ethyl-3-trimethoxysilyl-2-methylpropanamine, and the like.
[0037] Optionally, the curable sealant composition herein can also
contain one or more fillers such as calcium carbonate, precipitated
calcium carbonate, colloidal calcium carbonate, ground,
precipitated and colloidal calcium carbonates which is treated with
compounds such as stearate or stearic acid, reinforcing silicas
such as fumed silicas, precipitated silicas, silica gels and
hydrophobized silicas and silica gels; crushed and ground quartz,
alumina, aluminum hydroxide, titanium hydroxide, diatomaceous
earth, iron oxide, carbon black and graphite, talc, mica, and the
like.
[0038] In one aspect of the present invention, the filler component
of the curable composition is calcium carbonate, silica or a
mixture thereof. The type and amount of filler added depends upon
the desired physical properties for the cured silicone composition.
As such, the filler may be a single species or a mixture of two or
more species.
[0039] Other useful fillers can be nanoclays which possess a unique
morphology with one dimension being in the nanometer range. The
nanoclays can form chemical complexes with an intercalant that
ionically bonds to surfaces in between the layers making up the
clay particles. This association of intercalant and clay particles
results in a material which is compatible with many different kinds
of host resins permitting the clay filler to disperse therein.
[0040] When describing the nanoclays of the present invention, the
following terms have the following meanings, unless otherwise
indicated.
[0041] The term "exfoliation" as used herein describes a process
wherein packets of nanoclay platelets separate from one another in
a polymer matrix. During exfoliation, platelets at the outermost
region of each packet cleave off, exposing more platelets for
separation.
[0042] The term "gallery" as used herein describes the space
between parallel layers of clay platelets. The gallery spacing
changes depending on the nature of the molecule or polymer
occupying the space. An interlayer space between individual
nanoclay platelets varies, again depending on the type of molecules
that occupy the space.
[0043] The term "intercalant" as used herein includes any
inorganic, organic or semi-organic compound capable of entering the
clay gallery and bonding to the surface.
[0044] The term "intercalate" as used herein designates a
clay-chemical complex wherein the clay gallery spacing has
increased due to the process of surface modification. Under the
proper conditions of temperature and shear, an intercalate is
capable of exfoliating in a resin matrix.
[0045] The expression "modified clay" as used herein designates a
clay material that has been treated with any inorganic, organic or
semi-organic compound that is capable of undergoing ion exchange
reactions with the cations present at the interlayer surfaces of
the clay.
[0046] The term "nanoclay" as used herein describes clay materials
that possess a unique morphology with one dimension being in the
nanometer range. Nanoclays can form chemical complexes with an
intercalant that ionically bonds to surfaces in between the layers
making up the clay particles. This association of intercalant and
clay particles results in a material which is compatible with many
different kinds of host resins permitting the clay filler to
disperse therein.
[0047] The expression "organic nanoclay" as use herein describes a
nanoclay that has been treated or modified with an organic
intercalant.
[0048] The term "organoclay" as used herein designates a clay or
other layered material that has been treated with organic molecules
(variously referred to as "exfoliating agents," "surface modifiers"
or "intercalants") that are capable of undergoing ion exchange
reactions with the cations present at the interlayer surfaces of
the clay.
[0049] The nanoclays can be natural or synthetic materials. This
distinction can influence the particle size and for this invention,
the particles should have a lateral dimension of between about 0.01
.mu.m and about 5 .mu.m, and preferably between about 0.05 .mu.m
and about 2 .mu.m, and more preferably between about 0.1 .mu.m and
about 1 .mu.m. The thickness or the vertical dimension of the
particles can in general vary between about 0.5 run and about 10 nm
and preferably between about 1 nm and about 5 nm.
[0050] Useful nanoclays for providing the filler component include
natural or synthetic phyllosilicates, particularly smectic clays
such as montmorillonite, sodium montmorillonite, calcium
montmorillonite, magnesium montmorillonite, nontronite, beidellite,
volkonskoite, laponite, hectorite, saponite, sauconite, magadite,
kenyaite, sobockite, svindordite, stevensite, talc, mica,
kaolinite, vermiculite, halloysite, aluminate oxides, or
hydrotalcites, and the like, and their mixtures. In another
embodiment, useful layered materials include micaceous minerals
such as illite and mixed layered illite/smectite minerals such as
rectorite, tarosovite, ledikite and admixtures of illites with one
or more of the clay minerals named above. Any swellable layered
material that sufficiently sorbs the organic molecules to increase
the interlayer spacing between adjacent phyllosilicate platelets to
at least about 5 angstroms, or to at least about 10 angstroms,
(when the phyllosilicate is measured dry) can be used to provide
the curable compositions of the invention.
[0051] In one embodiment of the present invention, organic and
inorganic compounds useful for treating or modifying the clays and
layered materials include cationic surfactants such as ammonium,
ammonium chloride, alkylammonium (primary, secondary, tertiary and
quaternary), phosphonium or sulfonium derivatives of aliphatic,
aromatic or arylaliphatic amines, phosphines or sulfides.
[0052] Other organic treating agents for nanoclays that can be used
herein include amine compounds and/or quaternary ammonium compounds
R.sup.6 R.sup.7 R.sup.8N.sup.+X.sup.- each independently is an
alkoxy silane group, alkyl group or alkenyl group of up to 60
carbon atoms and X is an anion such as Cl.sup.-, F.sup.-,
SO.sub.4.sup.-, etc.
[0053] The compositions of the present invention can also include
one or more non-ionic surfactants such as polyethylene glycol,
polypropylene glycol, ethoxylated castor oil, oleic acid
ethoxylate, alkylphenol ethoxylates, copolymers of ethylene oxide
(EO) and propylene oxide (PO) and copolymers of silicones and
polyethers (silicone polyether copolymers), copolymers of silicones
and copolymers of ethylene oxide and propylene oxide and mixtures
thereof.
[0054] The curable compositions of the present invention can
include still other ingredients that are conventionally employed in
RTC silicone-containing compositions such as colorants, pigments,
plasticizers, cure accelerators, thixotropic agents, moisture
scavengers, dyes, solvents, antioxidants, UV stabilizers, biocides,
etc., in known and conventional amounts provided they do not
interfere with the properties desired for the cured
compositions.
[0055] The amounts of moisture-curable silylated resin (a), other
polymer (b), and optional components, such as, filler(s),
crosslinking catalyst(s), adhesion promoter(s) and ionic
surfactant(s) disclosed herein can vary widely and, advantageously,
can be selected from among the ranges indicated in the following
table. TABLE-US-00001 TABLE 1 Ranges of Amounts (Weight Percent) of
the Components of the Moisture-Curable Silylated Resin-Containing
Composition of the Invention Components of the First Second Third
Composition Range Range Range moisture-curable silylated 1-99 10-50
20-30 resin (a) other polymer (b) 1-99 5-50 10-20 filler(s) 0.1-80
10-60 20-55 Catalyst(s) 0.001-1 0.003-0.5 0.005-0.2 Silane Adhesion
0-20 0.3-10 0.5-2 Promoter(s) Ionic Surfactant(s) 0-10 0.1-5
0.5-0.75
[0056] The cured sealant compositions herein can be obtained by
procedures that are well known in the art, e.g., melt blending,
extrusion blending, solution blending, dry mixing, blending in a
Banbury mixer, etc., in the presence of moisture to provide a
substantially homogeneous mixture.
[0057] While the preferred embodiment of the present invention has
been illustrated and described in detail, various modifications of,
for example, components, materials and parameters, will become
apparent to those skilled in the art, and it is intended to cover
in the appended claims all such modifications and changes which
come within the scope of this invention.
* * * * *